code: def test_pdf_no_roots(self):
      with warnings.catch_warnings():
          warnings.simplefilter("error", RuntimeWarning)
          ne = ExpandedNormal([0, 1])
          ne = ExpandedNormal([0, 1, 0.1, 0.1])
  
imports: import warnings
  import numpy
  from numpy.testing import assert_equal, assert_raises, assert_allclose
  import numpy.testing
  from scipy.special import gamma, factorial, factorial2
  import scipy.stats
  from statsmodels.distributions.edgeworth import _faa_di_bruno_partitions, cumulant_from_moments, ExpandedNormal
label_desc: Use image node_id 5 for calling the TestExpandedNormal obj's underlying member method code with example usage: obj.test_pdf_no_roots() without return types